Hydraulic presentation

1. LRT HYDRAULIC BRAKE
SYSTEM WITH BOTH
DRUM AND DISC BRAKE
Kirubel Moges
GSR/4561/14

2. CONTENT
• Construction, Types, And Operation
• Possible Problems In The System And Components
• Monitoring and Measuring Instruments Used For The
Problem’s Identification
• Results obtained from monitoring and measurements and
deviation from standard values
• Corrective measures to be taken to solve the problems
• Summary​

3. PRIMARY GOALS
• Introducing the AALRT disk brake
system
• Distinguishing possible problems
caused in the train
• Introducing measuring devices and
results obtained from the
measurement
• Suggesting possible corrective
measures for the problems

4. CONSTRUCTION, TYPES, AND OPERATION
ABABA LIGHT RAIL TRAIN BRAKING SYSTEM
The AALRT braking system design is for a maximum speed of 70 km/h. The
vehicle is equipped with 2 motor bogies and 1 trailer bogie each fitted with different
brake systems:
• Electro dynamic (ED) brake system in a motor bogie, controlled by TCU
• Passive step-less electro-hydraulic (EH) friction brake system in trailer bogie,
controlled by BCU (Bogie Control Unit)
• Passive 3-step EH friction brake system in a motor bogie, controlled by VCU via
HCM
• Magnetic track brake(MTB) units in each bogie, controlled by wiring and VCU
However, regarding the electrohydraulic brake system, for the motor car, a brake
disc is installed on the axle whereas, for the trailer car, each wheel is given a
separate brake caliper. The braking system components were categorized in terms
of classes for the sub-components as shown in fig. 1
ie
• Class 1; braking systems
• Class 2; Class 1 components
• Class 3: Class 2 sub-components
4

5. FIG 1. AALRT BRAKING SYSTEM COMPONENTS
5

6. FIG 1. PIPING SCHEMATIC OF ELECTRO-HYDRAULIC SYSTEM 6

7. Cont. . . 7

8. HYDRAULIC UNIT 8

9. TYPES OF BRAKE ON LRT
9
ED BRAKE SYSTEM
• The electro dynamic
brake (ED brake) is wear-
free thus preferred to be
used in the brake
• The ED is also referred to
as regenerative braking
normally used where the
load on the motor has
very high inertia (e.g. in
EMU).
EH BRAKE SYSTEM
• EH brake system in motor
bogie. EH brake in motor
bogie is controlled by the
vehicle control unit (VCU)
via I/Os and will be used if
the ED brake of the
specific bogie fails.
• EH brake system in trailer
bogie. EH brake in trailer
bogie is controlled by
BCU. Brake pressure can
be adjusted continuously.
MAGNETIC TRACK BRAKE
(MTB)
• The MTB is used as an
emergency brake that is
not dependent on wheel-
rail adhesion. The
retarding effect of
adhesive brakes eg
hydraulic friction brakes is
significantly impacted by
the adhesion between the
wheel-rail.

10. POSSIBLE PROBLEMS
10
THERMAL
DEFORMATION
• Radial
expansion
• Coning
• Waving
• Rippling
OVERHEATING
OF BRAKES
• Brake Fade:
• Brake Fluid
• Vaporization
• Excessive
• Component
Wear
• Thermal Judde

11. TRAIN DISK PROBLEMS
11

12. POSSIBLE PROBLEMS IN THE SYSTEM AND
COMPONENTS
12
Hydrauli
c control
module
Bogie
Control
Unit
Hydraulic
Unit

13. CONT . . 13

14. CONT . . 14

15. CONT . . 15

16. CONT . .
16

17. CONT . .
17

18. CONT . . 18

19. MONITORING AND MEASURING
INSTRUMENTS USED FOR THE PROBLEM’S
IDENTIFICATION
19
BRAKE CYLINDERS TEST
BENCH
• With two types of brake
cylinders with or without
calipers.
• Do the automatic testing of the
force, leakage, and stroke and
check the brake pad adjuster,
by meeting the testing
standards of all major brake
cylinder manufacturers.
• The quality of the components
being used, along with an
automatic calibration procedure,
PORTABLE BRAKE TEST
EQUIPMENT
• To test the brake pneumatic
system of the single coach, the
entire train, or the freight wagon.
• Automatic testing and a single
operator
• Along with the equipment, a
compressor to independently
generate compressed air can be
provided
• Allows the testing of the brake
panel dismounted from the train

20. BRAKE TEST BENCH
BRAKE CONTROL PANELAND
INDICATOR UNIT

21. RESULTS OBTAINED FROM MONITORING AND
MEASUREMENTS AND DEVIATION FROM
STANDARD VALUES
• Done troubleshooting
• Tells us whether it is used fully or not
• Leeds us to apply different maintenance types
1. Breakdown maintenance
2. Condition-based maintenance (CBM)
3. Total Productive Maintenance (TPM)
4. Design upgrade/ Design out Maintenance
• When the disk surface thickness lower
• Emergency Braking
21

22. CORRECTIVE MEASURES TO BE TAKEN TO SOLVE THE
PROBLEMS 22

23. CONT .. 23

24. CONT . . 24

25. SUMMARY
25
Mechanical components such as discs, and caliper called for
more attention than the other components in terms of
maintenance as suggested by the manufacturer’s maintenance
manual. Concerning safety, the overall results showed that
CBM and TPM are suitable for the light rail trains.

26. THANK YOU

27. BRAKE CONTROL PANEL AND INDICATOR UNIT 27

28. CONT.
28

29. CONT.
29